Science shows intermittent fasting diet could extend life

Think of it as interval training for the dinner table. Proponents of fasting style diets will be first to tell you there are health benefits, heck we’ve even covered some of the science here at the labs. Well new research shows that putting people on a intermittent fasting (or IF) diet may mimic some of the benefits of actual fasting, and that (ironically enough given their popularity) adding antioxidant supplements counteracts those benefits.

Fasting has been shown in mice to extend lifespan and to improve age-related diseases. But fasting every day, which could entail skipping meals or simply reducing overall caloric intake, can be hard to maintain — not to mention counter productive when you think about it.

“People don’t want to just under-eat for their whole lives,” said Martin Wegman, an M.D.-Ph.D.

“We started thinking about the concept of intermittent fasting.”

“We found that intermittent fasting caused a slight increase to SIRT 3, a well-known gene that promotes longevity and is involved in protective cell responses,” Michael Guo, M.D.-Ph.D said.

The SIRT3 gene encodes a protein also called SIRT3. The protein SIRT3 belongs to a class of proteins called sirtuins. Sirtuins, if increased in mice, can extend their lifespans. Researchers think proteins such as SIRT3 are activated by oxidative stress, which is triggered when there are more free radicals produced in the body than the body can neutralize with antioxidants.

There has been a surge in recent years from marketing and “alternative health” websites suggesting that we should increase our antioxidant intake to counteract free radicals. However, small levels of free radicals can be beneficial: When the body undergoes stress — which happens during fasting — small levels of oxidative stress can trigger protective pathways.

“The hypothesis is that if the body is intermittently exposed to low levels of oxidative stress, it can build a better response to it,” Wegman said.

The researchers found that the intermittent fasting decreased insulin levels in the participants, which means the diet could have an anti-diabetic effect as well.

The group recruited 24 study participants in the double-blinded, randomized clinical trial. During a three-week period, the participants alternated one day of eating 25 percent of their daily caloric intake with one day of eating 175 percent of their daily caloric intake. For the average man’s diet, a male participant would have eaten 650 calories on the fasting days and 4,550 calories on the feasting days. To test antioxidant supplements, the participants repeated the diet but also included vitamin C and vitamin E.

At the end of the three weeks, the researchers tested the same health parameters. They found that the beneficial sirtuin proteins such as SIRT 3 and another, SIRT1, tended to increase as a result of the diet. However, when antioxidants were supplemented on top of the diet, some of these increases disappeared. This is in line with the research that indicates flooding the system with supplemental antioxidants may counteract the effects of fasting or exercise (and can accelerate the growth of cancer).

“You need some pain, some inflammation, some oxidative stress for some regeneration or repair,” said Christiaan Leeuwenburgh, Ph.D., co-author of the paper.

“These young investigators were intrigued by the question of whether some antioxidants could blunt the healthy effects of normal fasting.”

On the study participants’ fasting days, they ate foods such as roast beef and gravy, mashed potatoes, Oreo cookies and orange sherbet — but they ate only one meal. On the feasting days, the participants ate bagels with cream cheese, oatmeal sweetened with honey and raisins, turkey sandwiches, apple sauce, spaghetti with chicken, yogurt and soda — and lemon pound cake, Snickers bars and vanilla ice cream.

“Most of the participants found that fasting was easier than the feasting day, which was a little bit surprising to me,” Guo said.

“On the feasting days, we had some trouble giving them enough calories.”

The team says that future studies should examine a larger cohort of participants and should include studying a larger number of genes in the participants as well as examining muscle and fat tissue.

While anyone savvy enough to do the math will see that if you eat 25 percent of your daily required calories one day and 175 percent the next you will hit your base-line and in effect not lose (or gain) weight, there are people who use IF for dieting purposes. I myself have tried IF for weight loss reasons and found it to be easier than the traditional static lower calorie diets that most people use. However, as with anything, your mileage may vary and you need to find what works for you. In any case, if you can maintain eating in this manner, you could live longer and that is pretty impressive.